/Engine/Plugins/Developer/Concert/ConcertMain/Source/Concert/Public/IConcertSession.h
Register a custom event handler for this session
template<typename EventType> [FDelegateHandle](API\Runtime\Core\Delegates\FDelegateHandle) RegisterCustomEventHandler ( typename [TConcertFunctionSessionCustomEventHandler](API\Plugins\Concert\TConcertFunctionSessionCustomEve-)< EventType >::FFuncType Func )